Modulation Of Wnt Signaling Research Articles

R-Spondin 1 Suppresses Inflammatory Cytokine Production in Human Cortical Astrocytes

Background/Objectives: Wnt signaling pathways are essential in various biological processes, including embryonic development and tissue homeostasis, and are implicated in many diseases. The R-Spondin (RSpo) family, particularly RSpo1, plays a significant role in modulating Wnt signaling. This study aims to explore how RSpo1 binding to astrocytic LGR6 receptors influences central nervous system (CNS) homeostasis, particularly in the context of inflammation. Methods: Human-induced pluripotent stem cell-derived astrocytes were treated with RSpo1 to assess its impact on inflammatory cytokine release. A proteomic analysis was conducted using a Human Cytokine Array Kit to measure differential protein expression. Pathway enrichment analysis was performed to identify affected signaling pathways. Results: RSpo1 treatment led to a suppression of inflammatory cytokines such as IL-10, IFN-γ, and IL-23 in astrocytes, while TNF-α and CXCL12 levels were increased. Pathway analysis revealed significant alterations in key signaling pathways, including cytokine–cytokine receptor interaction, chemokine signaling, and TNF signaling pathways, suggesting RSpo1’s role in modulating immune responses within the CNS. Conclusions: RSpo1 significantly influences inflammatory responses in astrocytes by modulating cytokine release and altering key signaling pathways. These findings enhance our understanding of the interaction between cell-specific Wnt signaling and CNS inflammation, suggesting potential therapeutic applications of RSpo1 in neuroinflammatory and neurodegenerative diseases.

Zhuangyao Jianshen Wan ameliorates senile osteoporosis in SAMP6 mice through Modulation of the GCN5L1-mediated PI3K/Akt/wnt signaling pathway

BackgroundSenile osteoporosis (SOP) is a systemic bone disease characterized by increased susceptibility to fractures. However, there is currently no effective treatment for SOP. The Zhuangyao Jianshen Wan (ZYJSW) pill is traditionally believed to possess kidney-nourishing and bone-strengthening effects, demonstrating efficacy in treating fractures. Despite this, its effectiveness and mechanism in SOP remain unclear. This study aims to investigate the therapeutic potential of ZYJSW in treating SOP in senescence accelerated mouse prone 6 (SAMP6, P6) mice, and elucidate the underlying mechanisms. MethodsFour-month-old SAMP6 mice were categorized into six groups: the model group (SAMP6), low, medium, and high-dose ZYJSW treatment groups, calcitriol treatment (positive control 1) group, and metformin treatment (positive control 2) group. Gastric administration was carried out for 15 weeks, and a normal control group comprising four-month-old Senescence-Accelerated Mouse Resistant 1 (SAMR1) mice. Changes in body weight, liver and kidney function, bone protective effects, and muscle quality were evaluated using various assays, including H&E staining, Goldner staining, bone tissue morphology analysis, Micro-CT imaging, and biomechanical testing. Qualitative analysis and quality control of ZYJSW were performed via LC-MS/MS analysis. To explore mechanisms, network pharmacology and proteomics were employed, and the identified proteins were validated by Western blotting. ResultsOral administration of ZYJSW to P6 mice exerted preventive efficacy against osteopenia, impaired bone microstructure, and poor bone and muscle quality. ZYJSW attenuated the imbalance in bone metabolism by promoting bone formation, as evidenced by the upregulation of key factors such as Runt-related transcription factor 2 (RUNX2), Bone Morphogenetic Protein (BMP2), Osteoprotegerin (OPG) and Osteocalcin (OCN), while simultaneously inhibiting bone resorption through the downregulation of TNF receptor associated factor 6 (TRAF6), Tartrate resistant acid phosphatase (TRAP), Receptor activator for nuclear factor-κB ligand (RANKL) and Cathepsin K (CTSK). Additionally, ZYJSW enhanced muscle structure and function by counteracting the elevation of Ubiquitin (Ub), Muscle RING-finger protein-1 (Murf-1), F-Box Protein 32 (FBOX32), and Myogenin (Myog). Network pharmacology predictions, proteomics analysis corroborated by published literature demonstrated the role of ZYJSW involving in safeguarding mitochondrial biogenesis. This was achieved by suppressing GCN5L1 expression, contributing to the heightened expression of TFAM, PGC-1α, and nuclear respiratory factor-1 (NRF-1) proteins. ZYJSW also positively modulated Wnt signaling pathways responsible for bone formation, due to regulating expressions of key components like β-catenin, GSK-3β, and LRP5. In addition, ZYJSW causes the downregulation of the PI3K/Akt pathway by inhibiting the phosphorylation of both PI3K and Akt. ConclusionsThe study highlights the significance of ZYJSW in preserving the health of both bone and muscle in P6 mice, potentially through the regulation of the GCN5L1-mediated PI3K/Akt/Wnt signaling pathway. The translational potential of this articleOur research provides evidence and a mechanistic rationale for ZYJSW as a candidate for SOP treatment, offering insights for further exploration and strategy development.

Discovery of CLKs inhibitors for the treatment of non-small cell lung cancer

Targeted inhibition of the Wnt pathway is a promising strategy for treating NSCLC. CDC2-like kinase 2 (CLK2), a dual-specificity kinase responsible for phosphorylating serine/arginine-rich (SR) proteins, can modulate Wnt signaling through the alternative splicing of Wnt target genes, making CLK2 an attractive therapeutic target for NSCLC. In this study, we report the synthesis, optimization, and evaluation of CLK2 inhibitors that effectively suppress the proliferation of NSCLC cells, with the identification of the lead compound LBM22. Notably, compound LBM22 demonstrated potent inhibition of CLK2 (IC50 = 3.9 nM), leading to broad suppression of NSCLC cells proliferation and induction of apoptosis. Furthermore, LBM22 dose-dependently suppressed SR protein phosphorylation (pSRSF4, pSRSF5, and pSRSF6) in NSCLC cells, while downregulating the expression of Wnt pathway-related proteins (p-β-catenin, Axin 2, and c-Myc) as well as anti-apoptotic proteins (Bcl-2 and Mcl-1). Additionally, significant antiproliferative activity was observed for LBM22 in 3D cultured H1975OR cells. In conclusion, LBM22 emerges as a promising CLK2 inhibitor for the treatment of NSCLC.

Communication between cancer cell subtypes by exosomes contributes to nasopharyngeal carcinoma metastasis and poor prognosis.

Intratumor heterogeneity is common in cancers, with different cell subtypes supporting each other to become more malignant. Nasopharyngeal carcinoma (NPC), a highly metastatic cancer, shows significant heterogeneity among its cells. This study investigates how NPC cell subtypes with varying metastatic potentials influence each other through exosome-transmitted molecules. Exosomes were purified and characterized. MicroRNA expression was analyzed via sequencing and qRT-PCR. The effects of miR-30a-5p on migration, invasion, and metastasis were evaluated in vitro and in vivo. Its impact on desmoglein glycoprotein (DSG2) was assessed using dual-luciferase assays and Western blotting. Immunohistochemistry (IHC) and statistical models linked miR-30a-5p/DSG2 levels to patient prognosis. Different NPC cell subtypes transmit metastatic potential via exosomes. High-metastatic cells enhance the migration, invasion, and metastasis of low-metastatic cells through exosome-transmitted miR-30a-5p. Plasma levels of exosomal miR-30a-5p are reliable indicators of NPC prognosis. miR-30a-5p may promote metastasis by targeting DSG2 and modulating Wnt signaling. Plasma exosomal miR-30a-5p inversely correlates with DSG2 levels, predicting patient outcomes. High-metastatic NPC cells can increase the metastatic potential of low-metastatic cells through exosome-transmitted miR-30a-5p, which is a valuable prognostic marker assessable via liquid biopsy.

Unlocking Hope: Therapeutic Advances and Approaches in Modulating the Wnt Pathway for Neurodegenerative Diseases.

Neurodegenerative diseases (NDs) are conditions characterized by sensory, motor, and cognitive impairments due to alterations in the structure and function of neurons in the central nervous system (CNS). Despite their widespread occurrence, the exact causes of NDs remain largely elusive, and existing treatments fall short in efficacy. The Wnt signaling pathway is an emerging molecular pathway that has been linked to the development and progression of various NDs. Wnt signaling governs numerous cellular processes, such as survival, polarity, proliferation, differentiation, migration, and fate specification, via a complex network of proteins. In the adult CNS, Wnt signaling regulates synaptic transmission, plasticity, memory formation, neurogenesis, neuroprotection, and neuroinflammation, all essential for maintaining neuronal function and integrity. Dysregulation of both canonical and non-canonical Wnt signaling pathways contributes to neurodegeneration through various mechanisms, such as amyloid-β accumulation, tau protein hyperphosphorylation, dopaminergic neuron degeneration, and synaptic dysfunction, prompting investigations into Wnt modulation as a therapeutic target to restore neuronal function and prevent or delay neurodegenerative processes. Modulating Wnt signaling has the potential to restore neuronal function and impede or postpone neurodegenerative processes, offering a therapeutic approach for targeting NDs. In this article, the current knowledge about how Wnt signaling works in Alzheimer's disease and Parkinson's disease is discussed. Our study aims to explore the molecular mechanisms, recent discoveries, and challenges involved in developing Wnt-based therapies.

Chemically defined production of engineered cardiac tissue microspheres from hydrogel-encapsulated pluripotent stem cells.

Chemically defined, suspension culture conditions are a key requirement in realizing clinical translation of engineered cardiac tissues (ECTs). Building on our previous work producing functional ECT microspheres through differentiation of biomaterial encapsulated human induced pluripotent stem cells (hiPSCs), here we establish the ability to use chemically defined culture conditions, including stem cell media (E8) and cardiac differentiation media (chemically defined differentiation media with three components, CDM3). A custom microfluidic cell encapsulation system was used to encapsulate hiPSCs at a range of initial cell concentrations and diameters in the hybrid biomaterial, poly(ethylene glycol)-fibrinogen (PF), for the formation of highly spherical and uniform ECT microspheres for subsequent cardiac differentiation. Initial microsphere diameter could be tightly controlled, and microspheres could be produced with an initial diameter between 400 and 800 µm. Three days after encapsulation, cardiac differentiation was initiated through small molecule modulation of Wnt signaling in CDM3. Cardiac differentiation occurred resulting in in situ ECTformation; results showed that this differentiation protocol could be used to achieve cardiomyocyte (CM) contents greater than 90%, although there was relatively high variability in CM content and yield between differentiation batches. Spontaneous contraction of ECT microspheres initiated between Days 7 and 10 of differentiation and ECT microspheres responded to electrical pacing up to 1.5 Hz. Resulting CMs had well-defined sarcomeres and the gap junction protein, connexin 43, and had appropriate temporal changes in gene expression. In summary, this study demonstrated the proof-of-concept to produce functional ECT microspheres with chemically defined media in suspension culture in combination with biomaterial support of microsphere encapsulated hiPSCs.

Targeting WNT5B and WNT10B in osteosarcoma.

WNT signaling regulates osteosarcoma proliferation. However, there is controversy in the field of osteosarcoma as to whether WNT signaling is pro- or anti-tumorigenic. WNT-targeting therapeutics, both activators and inhibitors, are compared. WNT5B, a β-catenin-independent ligand, and WNT10B, a β-catenin-dependent WNT ligand, are each expressed in osteosarcomas, but they are not expressed in the same tumors. Furthermore, WNT10B and WNT5B regulate different histological subtypes of osteosarcomas. Using WNT signaling modulators as therapeutics may depend on the WNT ligand and/or the activated signaling pathway.

Bone Turnover Markers and Wnt Signaling Modulators in Early Complex Regional Pain Syndrome. A Pre-specified Observational Study.

To explore serum levels of some bone turnover markers and the involvement of the Wnt signaling in CRPS-1. Query ID="Q1" Text="Please check and confirm whether the edit made to the article title is in order." We conducted an observational study on patients with early CRPS-1 recruited before any treatment. Clinical measures were assessed together with biochemical evaluation. Values of sclerostin, DKK1, CTX-I, and P1NP were compared with sex-age-matched healthy controls (HCs). We enrolled 34 patients diagnosed with CRPS-1 (mean age 59.3 ± 10.6years, Male/Female 10/24), median disease duration = 2weeks (IQR 1-5); median VAS score = 76 (IQR 68-80). Foot localization was slightly more frequent than hand localization (18/16). No statistically significant difference was found between CRPS-1 patients and HCs for CTX-I (0.3 ± 0.1ng/ml vs 0.3 ± 0.1, p = 0.140), while mean serum values of P1NP were significantly higher in CRPS-1 patients compared to HCs (70.0 ± 38.8ng/ml vs 50.1 ± 13.6, p = 0.005). Mean levels of sclerostin and DKK1 were lower in CRPS-1 patients vs HCs (sclerostin 28.4 ± 10.8pmol/l vs 34.1 ± 11.6, p = 0.004; DKK1 12.9 ± 10.8pmol/l vs 24.1 ± 11.9, p = 0.001). No statistically significant difference was found for all biochemical assessments in a subgroup of fracture-induced CRPS-1. No statistically significant differences were observed according to disease localization, disease duration, presence of hyperalgesia, allodynia, sudomotor alterations, and mild or moderate/severe swelling. No significant correlation emerged between sclerostin, DKK1 levels, baseline VAS score, or McGill Pain Questionnaire score. Bone involvement in early CRPS-1 does not seem to rely on increased osteoclast activity. Conversely, a serum marker of bone formation resulted increased. Both Sclerostin and DKK1 showed decreased values, probably suggesting a widespread osteocyte loss of function.Trial registration number: Eudract Number: 2014-001156-28.

RECK/GPR124-driven WNT signaling in pancreatic and gastric cancer cells.

RECK has been described to modulate extracellular matrix components through negative regulation of MMP activities. Recently, RECK was demonstrated to bind to an orphan G protein-coupled receptor GPR124 to mediate WNT7 signaling in nontumor contexts. Here, we attempted to clarify the role of RECK in driving WNT signaling in cancer cells. RECK and GPR124 formed a complex in 293T cells, and when both were expressed, WNT signaling was significantly enhanced in a WNT7-dependent manner. This cooperation was abolished when RECK mutants unable to bind to GPR124 were transduced. RECK stimulated the growth of KRAS-mutated pancreatic ductal adenocarcinoma (PDAC) cells with increased sensitivity to WNT inhibitor in a GPR124-dependent manner. A gastric cancer cell line SH10TC endogenously expresses both RECK and GPR124 under regular culture conditions. In this cell line, inhibited cell growth and WNT signaling as well as increased apoptosis in the GPR124 depletion was dominantly found over those in the RECK deletion. These findings suggest that RECK promotes tumor cell growth by positively modulating WNT signaling through GPR124. This study proposes that the RECK/GPR124 complex might be a good therapeutic target in PDAC and gastric cancer.

The Low Tumorigenic Risk and Subtypes of Cardiomyocytes Derived from Human-induced Pluripotent Stem Cells

Background: Clinical application of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is a promising approach for the treatment of heart diseases. However, the tumorigenicity of hiPSC-CMs remains a concern for their clinical applications and the composition of the hiPSC-CM subtypes need to be clearly identified. Methods: In the present study, hiPSC-CMs were induced from hiPSCs via modulation of Wnt signaling followed by glucose deprivation purification. The structure, function, subpopulation composition, and tumorigenic risk of hiPSC-CMs were evaluated by single-cell RNA sequencing (scRNAseq), whole exome sequencing (WES), and integrated molecular biology, cell biology, electrophysiology, and/or animal experiments. Results: The high purity of hiPSC-CMs, determined by flow cytometry analysis, was generated. ScRNAseq analysis of differentiation day (D) 25 hiPSC-CMs did not identify the transcripts representative of undifferentiated hiPSCs. WES analysis showed a few newly acquired confidently identified mutations and no mutations in tumor susceptibility genes. Further, no tumor formation was observed after transplanting hiPSC-CMs into NOD-SCID mice for 3 months. Moreover, D25 hiPSC-CMs were composed of subtypes of ventricular-like cells (23.19%) and atrial-like cells (66.45%) in different cell cycle stages or mature levels, based on the scRNAseq analysis. Furthermore, a subpopulation of more mature ventricular cells (3.21%) was identified, which displayed significantly up-regulated signaling pathways related to myocardial contraction and action potentials. Additionally, a subpopulation of cardiomyocytes in an early differentiation stage (3.44%) experiencing nutrient stress-induced injury and heading toward apoptosis was observed. Conclusions: This study confirmed the biological safety of hiPSC-CMs and described the composition and expression profile of cardiac subtypes in hiPSC-CMs which provide standards for quality control and theoretical supports for the translational applications of hiPSC-CMs.

Spatial Multi-omics Reveals the Role of the Wnt Modulator, Dkk2, in Palatogenesis'.

Multiple genetic and environmental etiologies contribute to the pathogenesis of cleft palate, which is the most common of the inherited disorders of the craniofacial complex. Insights into the molecular mechanisms regulating osteogenic differentiation and patterning in the palate during embryogenesis are limited and needed for the development of innovative diagnostics and cures. This study used the Pax9-/- mouse model with a consistent phenotype of cleft secondary palate to investigate the role of Pax9 in the process of palatal osteogenesis. Although prior research has identified the upregulation of Wnt pathway modulators Dkk1 and Dkk2 in Pax9-/- palate mesenchyme, limitations of spatial resolution and technology restricted a more robust analysis. Here, data from single-nucleus transcriptomics and chromatin accessibility assays validated by in situ highly multiplex targeted single-cell spatial profiling technology suggest a distinct relationship between Pax9+ and osteogenic populations. Loss of Pax9 results in spatially restricted osteogenic domains bounded by Dkk2, which normally interfaces with Pax9 in the mesenchyme. Moreover, the loss of Pax9 leads to a disruption in the normal osteodifferentiaion of palatal osteogenic mesenchymal cells. These results suggest that Pax9-dependent Wnt signaling modulators influence osteogenic programming during palate formation, potentially contributing to the observed cleft palate phenotype.

Examination of wnt signaling mediated melanin transport and shell color formation in Pacific oyster (Crassostrea gigas)

Mollusca exhibit remarkable diversity in shell coloration, attributed to the presence of melanin, a widely distributed pigment with various essential roles, such as mechanical strengthening, antioxidation and thermoregulation. However, the regulatory network governing melanogenesis and melanin transport in molluscs remains poorly understood. In this study, we conducted a systematic analysis of melanin distribution and transport in the Pacific oyster, utilizing light microscopy and high-resolution transmission electron microscopy. In addition, we characterized CgWnt1 and CgWnt2b-a in Crassostrea gigas, and analyzed Wnt signaling in melanocyte formation. Expression analysis revealed that these genes were predominantly expressed in the mantle of black-shelled individuals, particularly in the outer fold of the mantle. Furthermore, we employed RNA interference and inhibitors to specifically inhibit Wnt signaling in both in vivo and in vitro. The results revealed impaired melanogenesis and diminished tyrosinase activity upon Wnt signaling inhibition. These findings suggest the crucial role of Wnt ligands and downstream factors in melanogenesis. In summary, our study provides valuable insights into the regulatory mechanism of shell pigmentation in C. gigas. By demonstrating the promotion of melanogenesis through Wnt signaling modulation, we contribute to a better understanding of the complex processes underlying molluscan melanin production and shell coloration.

Optimizing Nodal, Wnt and BMP signaling pathways for robust and efficient differentiation of human induced pluripotent stem cells to intermediate mesoderm cells.

Several differentiation protocols have enabled the generation of intermediate mesoderm (IM)-derived cells from human pluripotent stem cells (hPSC). However, the substantial variability between existing protocols for generating IM cells compromises their efficiency, reproducibility, and overall success, potentially hindering the utility of urogenital system organoids. Here, we examined the role of high levels of Nodal signaling and BMP activity, as well as WNT signaling in the specification of IM cells derived from a UCSD167i-99-1 human induced pluripotent stem cells (hiPSC) line. We demonstrate that precise modulation of WNT and BMP signaling significantly enhances IM differentiation efficiency. Treatment of hPSC with 3μM CHIR99021 induced TBXT+/MIXL1+ mesoderm progenitor (MP) cells after 48h of differentiation. Further treatment with a combination of 3μM CHIR99021 and 4ng/mL BMP4 resulted in the generation of OSR1+/GATA3+/PAX2+ IM cells within a subsequent 48h period. Molecular characterization of differentiated cells was confirmed through immunofluorescence staining and RT-qPCR. Hence, this study establishes a consistent and reproducible protocol for differentiating hiPSC into IM cells that faithfully recapitulates the molecular signatures of IM development. This protocol holds promise for improving the success of protocols designed to generate urogenital system organoids in vitro, with potential applications in regenerative medicine, drug discovery, and disease modeling.

Diagnostic and prognostic significance of circulating secreted frizzled-related protein 5 in colorectal cancer.

Secreted Frizzled-Related Protein 5 (SFRP5) modulates Wnt signalling pathways, affecting diverse biological processes. We assessed the diagnostic and prognostic value of circulating SFRP5 (cSFRP5) in colorectal cancer (CRC) METHODS: Plasma cSFRP5 concentrations were measured using enzyme-linked immunosorbent assay (ELISA) in healthy donors (n = 133), individuals diagnosed with CRC (n = 449), colorectal polyps (n = 85), and medical conditions in other organs including cancer, inflammation, and benign states (n = 64). Patients with CRC, polyps, and other conditions showed higher cSFRP5 levels than healthy individuals (p < 0.0001). Receiver operating characteristic curves comparing healthy donors with medical conditions, polyps and CRC were 0.814 (p < 0.0001), 0.763 (p < 0.0001) and 0.762 (p < 0.0001), respectively. In CRC, cSFRP5 correlated with patient age (p < 0.0001), tumour stage (p < 0.0001), and histological differentiation (p = 0.0273). Levels, adjusted for patient age, sex, plasma age and collection institution, peaked in stage II versus I (p < 0.0001), III (p = 0.0002) and IV (p < 0.0001), were lowest in stage I versus III (p = 0.0002) and IV (p = 0.0413), with no difference between stage III and IV. Elevated cSFRP5 levels predicted longer overall survival in stages II-III CRC (univariate: HR 1.82, 95% CI: 1.02-3.26, p = 0.024; multivariable: HR 2.34, 95% CI: 1.12-4.88, p = 0.015). This study confirms cSFRP5 levels are elevated in CRC compared to healthy control and reveals a correlation between elevated cSFRP5 and overall survival in stages II-III disease.

Enhancing motor functional recovery in spinal cord injury through pharmacological inhibition of Dickkopf-1 with BHQ880 antibody

BackgroundMounting experimental evidence has underscored the remarkable role played by the Wnt family of proteins in the spinal cord functioning and therapeutic potential in spinal cord injury (SCI). We aim to provide a therapeutic prospect associated with the modulation of canonical Wnt signaling, examining the spatio-temporal expression pattern of Dickkopf-1 (Dkk1) and its neutralization after SCI. We employ an intraparenchymal injection of the clinically validated Dkk1-blocking antibody, BHQ880, to elucidate its effects in SCI. MethodsA rat model of contusion SCI was used. Histological analyses were performed, wherein Dkk1 protein was sought, and ELISA analyses were employed for Dkk1 detection in cerebrospinal fluid and serum. To ascertain the BHQ880 therapeutic effect, rats were subjected to SCI and then injected with the antibody in the lesion epicenter 24 hours post-injury (hpi). Subsequent evaluation of motor functional recovery extended up to 56 days post-injury (dpi). qRT-PCR and histological analyses were conducted. ResultsWe demonstrate the presence of Dkk1 in the healthy rat spinal cord, with pronounced alterations observed following injury, primarily concentrated in the epicenter regions. Notably, a significative upregulation of Dkk1 was detected at 24 hpi, peaking at 3 dpi and remaining elevated until 42 dpi. Moreover, we revealed that early administration of BHQ880 considerably improved motor functional recovery, promoted preservation of myelinated tissue, and reduced astroglial and microglia/macrophage reactivity. Furthermore, there was a decrease in the acute expression of different inflammatory genes. ConclusionsCollectively, our findings highlight the therapeutic potential of BHQ880 treatment in the context of SCI.

Dickkopf-1 (DKK1) drives growth and metastases in castration-resistant prostate cancer.

Metastatic castration-resistant prostate cancer (mCRPC) is associated with a poor prognosis and remains an incurable fatal disease. Therefore, the identification of molecular markers involved in cancer progression is urgently needed to develop more-effective therapies. The present study investigated the role of the Wnt signaling modulator Dickkopf-1 (DKK1) in the growth and metastatic progression of mCRPC. DKK1 silencing through siRNA and deletion via CRISPR/Cas9 editing were performed in two different metastatic castration-resistant prostate cancer cell lines (PC3 and DU145). A xenograft tumor model was used to assess tumor growth and metastases. In in vitro experiments, both DKK1 silencing and deletion reduced cell growth and migration of both cell lines. DKK1 knockout clones (DKK1-KO) exhibited cell cycle arrest, tubulin reorganization, and modulation of tumor metastasis-associated genes. Furthermore, in DKK1-KO cells, E-cadherin re-expression and its membrane co-localization with β-catenin were observed, contributing to reduced migration; Cadherin-11, known to increase during epithelial-mesenchymal transition, was down-regulated in DKK1-KO cells. In the xenograft mouse model, DKK1 deletion not only reduced tumor growth but also inhibited the formation of lung metastases. In conclusion, our findings support the key role of DKK1 in the growth and metastatic dissemination of mCRPC, both in vitro and in vivo.

ΔNp63 regulates Sfrp1 expression to direct salivary gland branching morphogenesis.

Branching morphogenesis is a complex process shared by many organs including the lungs, kidney, prostate, as well as several exocrine organs including the salivary, mammary and lacrimal glands. This critical developmental program ensures the expansion of an organ's surface area thereby maximizing processes of cellular secretion or absorption. It is guided by reciprocal signaling from the epithelial and mesenchymal cells. While signaling pathways driving salivary gland branching morphogenesis have been relatively well-studied, our understanding of the underlying transcriptional regulatory mechanisms directing this program, is limited. Here, we performed in vivo and ex vivo studies of the embryonic mouse submandibular gland to determine the function of the transcription factor ΔNp63, in directing branching morphogenesis. Our studies show that loss of ΔNp63 results in alterations in the differentiation program of the ductal cells which is accompanied by a dramatic reduction in branching morphogenesis that is mediated by dysregulation of WNT signaling. We show that ΔNp63 modulates WNT signaling to promote branching morphogenesis by directly regulating Sfrp1 expression. Collectively, our findings have revealed a novel role for ΔNp63 in the regulation of this critical process and offers a better understanding of the transcriptional networks involved in branching morphogenesis.

A PAK family kinase and the Hippo/Yorkie pathway modulate WNT signaling to functionally integrate body axes during regeneration

Successful regeneration of missing tissues requires seamless integration of positional information along the body axes. Planarians, which regenerate from almost any injury, use conserved, developmentally important signaling pathways to pattern the body axes. However, the molecular mechanisms which facilitate cross talk between these signaling pathways to integrate positional information remain poorly understood. Here, we report a p21-activated kinase (smed-pak1) which functionally integrates the anterior-posterior (AP) and the medio-lateral (ML) axes. pak1 inhibits WNT/β-catenin signaling along the AP axis and, functions synergistically with the β-catenin-independent WNT signaling of the ML axis. Furthermore, this functional integration is dependent on warts and merlin-the components of the Hippo/Yorkie (YKI) pathway. Hippo/YKI pathway is a critical regulator of body size in flies and mice, but our data suggest the pathway regulates body axes patterning in planarians. Our study provides a signaling network integrating positional information which can mediate coordinated growth and patterning during planarian regeneration.

Modulation of WNT signalling by inflammatory factor TWEAK, and its consequences on fibroblast-epithelial communication

BACKGROUND AND AIMS: A single layer of epithelial cells that are supported by resident mucosal fibroblasts, provides an intestinal barrier against pathogens. In Inflammatory Bowel Disease (IBD), this barrier is disrupted by mechanisms which are poorly understood. Intestinal fibroblasts produce WNT, BMP and Notch mediators that contribute to epithelial homeostasis and an impairment on these signals results in the loss of barrier integrity which has been observed in IBD. In fact, fibroblasts producing these signals may be lost during inflammation. Yet the mediators and mechanism that drive this loss of homeostatic stromal-derived signals are unknown. TWEAK is a member of the tumour necrosis factor superfamily (TNFSF) that was found to be upregulated in IBD biopsies and dysregulated tissue repair and promote chronic inflammation in in vivo murine models. However, whether TWEAK exerts its effects on fibroblasts and how these may contribute to barrier breakdown remains unknown. My central hypothesis is that TWEAK dysregulates the crosstalk between fibroblasts and epithelial cells in the intestinal tract by impairing a homeostatic signalling network. METHODS: To assess the effect of TWEAK on WNT signalling and wound healing in fibroblasts and epithelial cells, the expression of WNT ligands and receptors were assessed. Primary human colonic fibroblasts and human colonic epithelial cells were stimulated with TWEAK at various time points and analysed by qPCR, Western blot and Flow cytometry and scratch wound assay. RESULTS: Both Fibroblasts and epithelial cells displayed abundant Fn14 surface receptor, although epithelial cells at a level lower than that found on colonic fibroblasts. Transcriptional signatures at gene RSPO2 (0.5-fold ± decrease, *p&lt;0.05, n=4), WNT5A (1 fold ± decrease, **p&lt;0.01, n=4) and BMP6 (1 fold ± decrease, ***p&lt;0.001, n=4) and protein level RSPO2 (50% ± decrease respectively, n=5) showed a TWEAK-mediated suppression after prolonged exposure (24-48h), but not in epithelial cells. Moreover, TWEAK delayed fibroblast healing capacity after 24h (50% ± decrease in wound closure, n=4) in a wound-scratch assay. CONCLUSION: TWEAK represses the expression of homeostatic factors in colonic fibroblasts but not on epithelial cells, suggesting this mechanism could be specific to the intestinal stroma. The effect that this impairment of WNT signals in stromal cells may have on their differentiation and communication with the epithelium will be subject for further study. UCD Ad Astra PhD Scholarship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Notum protects against myocardial infarction-induced heart dysfunction by alleviating cardiac fibrosis

Abstract Background and Objective Cardiac fibrosis is a pathological reparative process that follows myocardial infarctionand is associated with compromised cardiac systolic and reduced cardiac compliance. The Wnt signaling pathway is closely implicated in organ fibrosis, and Notum, a highly conserved secreted inhibitor, modulates Wnt signaling. The objective of this study was to explore the role and mechanism of Notum in cardiac fibrosis. Methods A mouse model of cardiac remodeling was established through left coronary artery ligation surgery, with the addition of Notum injection following myocardial infarction surgery. The protective effect of Notum on myocardial infarction was assessed by evaluating cardiac function, including survival rate, echocardiographic assessment, and cardiac contraction analyses. Inflammatory cell necrosis and infiltration were confirmed through H&amp;E and Masson staining. The expression of fibrosis-related genes and β-catenin pathway markers was detected using Western blot quantificational RT-PCR (qRT-PCR). Additionally, EdU, wound healing, and immunofluorescence staining analyses were performed to detect the effect of Notum’s in transforming growth factor beta-1 (TGF-β1) induced myofibroblast transformation. Results The administration of Notum treatment resulted in enhanced survival rates, improved cardiac function, and decreased necrosis and infiltration of inflammatory cells in mice subjected to left coronary artery ligation. Furthermore, Notum effectively impeded the senescence of cardiac fibroblasts and hindered their pathological transformation into cardiac fibroblasts. Additionally, it significantly reduced collagen production and attenuated the activation of the Wnt/β-catenin pathway. Our preliminary investigations successfully demonstrated the therapeutic potential of Notum in both fibroblasts in vitro and in a mouse model of myocardial infarction-induced cardiac fibrosis in vivo. Conclusion Notum inhibition of the Wnt/β-catenin signaling pathway and cardiac fibroblast senescence ultimately hampers the onset of cardiac fibrosis. Our findings suggest that Notum could represent a new therapeutic strategy for the treatment of cardiac fibrosis.